Telescopic liquid tank

ABSTRACT

A tank is provided, including a tray positioned on a skid; an outer tank wall positioned within the tray; an inner tank wall positioned within the first outer tank wall; wherein the outer tank walls is moveable from a first position wherein the inner tank wall is substantially contained within the outer tank wall; and a second position wherein the moveable outer tank wall is elevated, thereby increasing the height and storage capacity of the tank.

RELATED APPLICATION

The present application claims the benefit of priority under 35 U.S.C. 119 to Canadian Patent Application Serial No. 2,778,306, filed May 25, 2012, and entitled “Telescopic Liquid Tank”, all of which is commonly owned herewith.

FIELD OF THE INVENTION

The invention relates to tanks for use in fracking operations, and more particularly large volume, transportable, steel water tanks for such use.

BACKGROUND OF THE INVENTION

Large volumes of water are required for hydraulic stimulation (referred to as fracture or fracking) of well sites. In order to store large volumes of water, either many traditional horizontal rectangular tanks, or many traditional vertical cylindrical tanks, are needed, often in conjunction with a geomembrane lined open top tank (such tanks are prone to damage and leaks).

Open top tanks are large volume tanks with a large surface footprint. They are usually circular, which is an inefficient use of space. Using open top tanks requires transferring fluid from the tank to a frack tank farm for use by the fracking equipment. Open top tanks are lined with a geomembrane liner that is fragile and prone to damage and leaks. The liner is not reusable, and is expensive to replace. Specialized pumping equipment is required to use with these tanks It is difficult to safely get all of the fluid in a tank from the tank bottom, resulting in some waste. Open top tanks are expensive to clean and decommission, and can cause a major incident in the case of tank failure, as there is no secondary containment. These tanks are not compartmentalized and in case of a failure, the entire volume of water may be lost. There are also limits on the height of these tanks, resulting in large footprints as the liquid capacity per area of land is low

Vertical cylindrical 400 bbl tanks are a standard oilfield tank, widely used in Canada. Volume of these tanks is normally 400 bbl, or 60 m³. At best, these tanks can be transported in pairs on one truck. The cylindrical tanks require elaborate manifolds and many hoses to properly connect the tanks for fracking use. As the tanks have no built in containment, the tank farm is typically bermed and lined. Matting is required underneath the tanks Matting and manifolds and hoses typically require at least one full additional truck load. The cylindrical tanks also take up a large footprint on an area/volume basis.

Rectangular tanks are either mobile via an axle, or are skidded, or such tanks are widely used in the U.S. These rectangular tanks may have volumes up to 100 m³, although 80 m³ is more common. These tanks have all the disadvantages of the vertical tanks, and require an even larger surface footprint. In addition, they can only be transported or moved as single tanks, which adds to the transportation and set up cost.

What the current tanks used in fracking operations lack is a built in secondary containment, and integrated or compatible pumping systems, as well as a tank design that is easily transportable but also high volume.

SUMMARY

The telescopic frack water tanks according to the invention provide large volume fluid storage, a compact footprint, with minimal transportation and installation cost. The system combines three components, namely a large volume horizontal telescopic tank that is highway transportable; has easily integrated pumping systems; and has built in secondary containment

The tank according to the invention is used to support the hydraulic stimulation (fracture) of shale gas wells. A pad operation for such frac operations likely includes at least three of these tanks, each having a volume of at least 500 m³. A first tank serves as a primary storage/receiving tank, and supplies fluid to a second tank. The second tank is used in place of the traditional fracking tank farm and suction manifold, and the fracking equipment blender and charge pumps are tied directly into the second tank. The third tank is used for flowback storage and transfer, replacing the traditional flowback tank farm.

Large volume storage is thereby realized via one transportable tank according to the invention. The tank is adjustable in height once delivered to the location, to allow for large volume capability. Setup and installation of the tank is fast, resulting in significant transportation cost savings. The incorporated containment prevents environmental spills, and the included recirculation pump transfers fluid from containment back into the tank, if necessary. The incorporated pumping systems and tank connections further increase functionality, and eliminate the need for additional equipment. Each tank can replace several standard vertical tanks, or standard horizontal tanks.

A system using the tanks according to the invention is capable of transferring high volumes of water to the fracking equipment, pumping at high pressure off the pad to offsite storage, and receiving and transferring flowback water to the primary pad storage tank. In addition, pumping systems allow for fluid circulation to prevent line freeze problems, as well as circulation through a water heater. Incorporated light masts can eliminate additional surface rentals, such as light towers, and incorporated weirs allow compartment separation and can be used for sand settling, chemical injection, and other functions.

A tank is provided, including: a tray positioned on a skid; a first tank wall positioned on the tray; a second inner tank wall positioned within the first inner tank wall; wherein the first tank wall is moveable from a first position wherein the second inner tank wall is substantially contained within the first tank wall; and a second position wherein said first tank wall is elevated thereby increasing the height and storage capacity of the tank.

When the first tank wall is in the second position, a seal is formed between the first tank wall and the second tank wall. The first tank wall is moveable from the first position to the second position by a plurality of hydraulic rams. The tank may include a pump positioned to pump water leaking through the seal to the tray back into the tank, or to another location, such as another tank. The seal may include a gasket between a bottom inside portion of the first tank wall and a top outside portion of the second tank wall. The seal may further include a plurality of inflatable hoses positioned between the second tank wall and the first tank wall.

A further tank is provided, including: a spill containment tray positioned on a skid; a first tank wall positioned on the tray; a second inner tank wall positioned within the first inner tank wall; wherein the second inner tank wall is moveable from a first position wherein the first outer tank wall substantially contains the second inner tank wall; and a second position wherein the second inner tank wall is elevated thereby increasing the height and storage capacity of the tank.

DESCRIPTION OF THE FIGURES

FIG. 1 is a side view of a tank according to the invention, in a raised position.

FIG. 2 is an end view thereof.

FIG. 3 is an end view thereof, showing the tank in a lowered position.

FIG. 4 is a top view thereof;

FIGS. 5A, 5B, 5C, and 5D are cross sectional views of fastening elements and sealing elements of the tanks walls according to the invention.

FIG. 6 is an end view of an alternative embodiment of the tank according to the invention.

FIG. 7 is a partial cross sectional view of an alternative embodiment of a sealing element for the tank.

FIG. 8 is a perspective view of a sealing member used in the sealing embodiment.

FIG. 9 is a cross sectional end view of an alternative embodiment of the tank according to the invention.

FIG. 10 is a cross sectional view of an embodiment of a seal therein, detailing C in FIG. 9.

FIG. 11 is a detailed view of an embodiment of a foldable platform in the tank, detailing B in FIG. 9.

FIG. 12A is a sectional view taken along C-C in FIG. 9 of an embodiment of a drip tray within the tank.

FIG. 12B is a side cross sectional view thereof, detailing A in FIG. 9.

FIG. 13 is a perspective view of an embodiment of a tank according to the invention.

FIGS. 14 a, 14 b, and 14 c are side cross sectional views of an alternate embodiment of the invention showing the raising of the tank wall.

FIG. 15 is a top view showing the corner of an embodiment of the tank according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The tank according to the invention includes horizontal tank 10, as shown in FIGS. 1 through 4. Tank 10 is secured to skids 20, and may be of the maximum (oversize) width, length, and height (when in a lowered position) permitted for travel by road.

Tank 10 includes closed outer tank 30 and closed inner tank wall 40. Inner tank wall 40 is sized to fit within outer tank 30, and can be raised telescopically to increase the overall wall height of tank 10 and thereby the storage capacity of tank 10. Further inner tank walls may be included in tank 10 in a nesting pattern to provide multiple telescopic interior tanks thereby providing increased height when the tank walls are raised.

Inner tank wall 40 is raised using a plurality of hydraulic lifts 50, positioned around the exterior wall 60 of outer tank 30. In a typical embodiment of the invention, six or more lifts 50 would be present to allow for even lifting of inner tank wall 40. FIGS. 1 and 2 shows inner tank wall 40 in a raised position.

As shown in FIGS. 5A through 5D, interior tank wall 40 creates a seal with the adjacent exterior wall 60 when the hydraulic lifts are fully extended, and pressure is forced upon opposite faces of wall 40 and wall 60. FIGS. 5A through 5D each represent an alternative sealing means. Additional sealing is provided by grease injection and gasket material 55 between inner tank wall 40 and exterior wall 60. Grease injection nipples 45 may be positioned at regular intervals to allow grease injection.

As seen in FIG. 5A, projection 100, at the bottom and outside of interior tank wall 40, is sized to fit indentation 110 at the top and inside of exterior wall 60. Gasket material 55 is positioned between projection 100 and indentation 110.

An alternative embodiment of sealing means is shown in FIG. 5B, in which mating projection 120 at the bottom outside edge of interior tank wall 40 meets the inner edge of mating projection 130 at the top inside edge of exterior tank wall 60 to form a seal. Gasket material 55 is positioned between projections 120, 130.

FIG. 5C shows another embodiment of sealing means, wherein dividers 140 at the bottom of inner tank wall 40 form channels 150. Inflatable rubber hoses 160 run through each channel 150, and are inflated when the inner tank wall 40 is raised. Between each rubber hose 160 and exterior wall 60 are rubber sealing gaskets 170.

FIG. 5D shows yet a further embodiment of sealing means, in which gasket 55 on pivotable member 180, is positionable under inner tank wall 40, after inner tank wall 40 has been raised. Inner tank wall 40 is then sealed using gravity as inner tank wall 40 rests on pivotable member 180 which pivots on hinge 185.

Containment tray 70 is positioned around the base 80 of exterior tank wall 60 to contain any leakage that may slip through the seals at the junction of interior tank wall 40 and exterior wall 60. A built in transfer pump (not shown) may be present to transfer any fluid collected in the containment tray back into the main tank 10.

Exterior wall 60 includes a plurality of flanged and valved connection ports (not shown) to allow for liquid transfer from the tank and reception of liquids from other sources.

FIG. 6 shows an alternative embodiment of tank 10 in which outer wall 200 is raise by hydraulic lifts 50 relative to inner wall 210. An example of sealing means for this embodiment is shown in FIG. 7, in which inward extension 220 at the bottom of outer wall 200 meets outer facing extension 230 of inner wall 210. Rubber inflatable seal members 240, as shown in FIG. 8, may be positioned on either inward extension 220 or outward extension 230 facing the other extension. When the rubber seal members 240 meet inward extension 220, members 240 flatten, and may be inflated by air or liquid, creating a seal between inner wall 210 and outer wall 200.

Tank floor 90 may be gently sloped and have a liquid outlet at the base 80 to allow for ease of extraction of the liquid therein. Built in pumping systems (not shown) may be present to allow transfer of liquid between tanks 10, transfer of liquid off site, and circulation of liquid through heaters and pipelines to prevent freezing. Alternatively, the pumping systems may be positioned nearby tank 10, and in liquid communication with tank 10 via hoses and the like.

When fracking job is finished, tank 10 is drained, inner tank wall 40 (or outer tank wall 200) is lowered to transport height, and tank 10 is winched onto standard high-bed tractor trailer, and can be moved from the site. Typical volume of tank 10 would be 500 m³, based on a two tier tank wall design.

FIG. 9 shows a side cross sectional view of another embodiment of a tank 10 according to the invention. In this embodiment of tank 10, outer wall 200 is elevatable. Foldable walking platform 215 is positioned around the interior of inner tank wall 210 to allow users access to tank 10, Outer wall 200 is shown in elevated position in dashed lines, and in unelevated position in solid lines.

FIG. 10 is a detailed view of C in FIG. 9, showing the sealing means. Guide 310 acts as a pinning plate to guide walls 200 and 210 into position. Pins 315 are then used to secure walls 200 and 210, by passing pins 315, 316 through aligned apertures (not shown) in each wall 200, 210. Pin 315 may be fixed in place while pin 316 is removable to allow outer wall 200 to be elevated or lowered. Seal members 240 are secured to the top of inner wall by screws or the like.

FIG. 11 shows a detailed view of B in FIG. 9, showing base 325 of walking platform 215 secured to inner wall 210.

FIG. 12A is a cross sectional top view of elevated outer wall 200 showing links 360. Links 360 are secured to outer wall 200 by pins 315, 316.

FIG. 12B is a detail of A showing the bottom portion of inner wall 210 and outer wall 200. Drip tray 330 provides secondary liquid containment and has lip 335 extending outwardly from outer wall 200.

FIG. 13 is a perspective view of tank 10 showing the frame of the inner wall 210 and outer wall 200. Extension 400 provides support and stability to tank 10. Pipes 410 allow for intake or removal of water or another fluid. Ladder 420 allows workers to reach the bottom of tank 10.

The bottom of tank 10 is supported by bottom cross beams 430. Support beams 440 extend vertically to support inner tank wall 210. Door 450 allows access to the interior of tank 10, for cleaning, or for a vacuum truck operator. Door 450 may be configured so that it cannot be opened when tank 10 is full to provide safety for workers nearby.

Outer wall 200 is supported vertically by vertical support beams 460 and upper horizontal cross members 470 and lower horizontal cross members 480. Upper frame member 490 maintains the shape of outer wall 200. Tank 10 is generally made of steel, with the exterior of outer wall 200 painted and the interior of inner wall 210 having an anti-corrosion coating.

Ring 500 surrounds the top of inner wall 210. Links 360 extend upwardly from ring 500. Attached to support beams 440 is walking platform 215.

FIGS. 14A, 14B and 14C show the process by which outer wall 200 raises. FIG. 14A shows outer wall in an unelevated state. Guide 860, which may be a pipe, has a links 890 at the top and bottom to allow it to be secured to or detached from wall 200. Wall 200 is positioned in-between guide 860 and guide 880, and is secured to hydraulic lift 338. Guide 880 is extendible and may rise with lift 338. The lower end of guide 880 is fixed in position.

FIG. 15 shows gusset 390 which is used by hydraulic lift 338 to raise wall 200. Guides 860 and 880 are on opposite sides of wall 200. Corners of tank 10 are cured to correspond to the bending of seals 240, which may not always permit a square corner.

When inner wall 210 and outer wall 200 are pinned together (i.e. the elevatable wall is not in an elevated position and the walls 200. 210 are secured by pins), hydraulic lift 338 can expand freely downward and act as a jack to lift the entire tank structure 10, as shown in FIG. 14B. This is used for loading and unloading tank 10 onto a trailer. The hydraulic lifts elevate tank 10 so that a trailer can be positioned underneath it.

Hydraulic lifts 50 also lift outer wall 200 from the inner wall 210. After tank 10 is unloaded, it is lowered to the ground. The two walls 200, 210 are now unpinned. Now when the hydraulic lifts 50 jacks extend, they lift outer wall 200 and separate the two walls 200, 210.

The above-described embodiments have been provided as examples, for clarity in understanding the invention. A person with skill in the art will recognize that alterations, modifications and variations may be effected to the embodiments described above while remaining within the scope of the invention as defined by claims appended hereto. 

What is claimed is:
 1. A tank, comprising: a. a spill containment tray positioned on a skid; b. an outer tank wall positioned within the spill containment tray; and c. an inner tank wall positioned within the outer tank wall, wherein the outer tank wall is moveable from a first position wherein the inner tank wall is substantially contained within the outer tank wall; and a second position wherein the outer tank wall is elevated thereby increasing the height and storage capacity of the tank.
 2. The tank of claim 1 wherein when the outer tank wall is in the second position, a seal is formed between the outer tank wall and the inner tank wall.
 3. The tank of claim 2 wherein the outer tank wall is moveable from the first position to the second position by a plurality of hydraulic lifts.
 4. The tank of claim 3 further comprising a pump configured to pump water leaking through the seal into the tray back to the tank.
 5. The tank of claim 4 wherein the seal further comprises a gasket between a bottom inside portion of the outer tank wall and a top outside portion of the inner tank wall.
 6. The tank of claim 4 wherein the seal further comprises a plurality of inflatable hoses positioned between the outer tank wall and the inner tank wall.
 7. A tank, comprising: a. a spill containment tray positioned on a skid; b. a first tank wall positioned within the spill containment tray; and c. a second moveable tank wall, wherein the moveable tank wall is moveable from a first position wherein the first and second tank walls are substantially aligned; and a second position wherein the moveable tank wall is elevated thereby increasing the height and storage capacity of the tank. 